MIL-PRF-1/839F
TABLE I. Requirements - Continued.
NOTES:
1.
See "Reduced pressure (altitude) rating," and altitude, maximum peak voltage in the basic document.
2.
This test shall be performed at the conclusion of the holding period.
3.
Prior to this test, the tubes under test (TUT) shall be preheated a minimum of 5 minutes operating at the
conditions specified below. The 3-minute test shall not be permitted. Test at specified conditions within 3
seconds after preheating. Grid emission shall be the last test performed on the sample selected for the grid
emission test.
Ef
Ec1
Eb
Rk/k
Rg/g Ec2
MegΩ Vdc
V
Vdc
Vdc
Ohms
7.5
0
120
125
0.01 120
4.
This test shall be conducted on the initial lot and thereafter on a lot approximately every 12 months. When
one lot has passed, the 12-month rule shall apply. In the event of lot failure, the lot shall be rejected and the
succeeding lots shall be subjected to this test until a lot passes.
5.
A grid resistor of 0.1 megohm shall be added except when a thyratron-type short indicator is used.
6.
Acceptance sampling procedure shall be in accordance with "Base-strain test, miniature, sampling (see MIL-
STD-1311, method 1121)", except that data covered in "Acceptance and rejection criteria" shall be modified
as follows:
a.
Accepted if not one defective for class "A", "B", or "C" defects, respectively (see MIL-STD-1311, method
1121), or if not one total defective is found in the sample.
b.
Rejected if one or more defectives for class "A", "B", or "C" defects, respectively, or if a total of one
defective or more is found in the sample.
7.
The life-test sample shall consist of 20 tubes per lot and no tube failure shall be permitted. In the event of
rejection of the first sample due to failure, a second sample of 20 tubes shall be selected from the lot.
Acceptance shall then be based on the second samples, with no failures allowed.
8.
Envelope temperature (TE) requirements, when measured in accordance with the temperature by conduction-
band measurement (see MIL-STD-1311, method 1226), will be satisfied if a TUT having bogey Ib (+5 percent)
under normal test conditions, is determined to operate at or above minimum specified temperature at any
position in the life test-rack.
9.
Marginal notations are not used in this revision to identify changes with respect to the previous issue, due to
the extensiveness of the changes.
10.
This specification sheet uses accept on zero defect sampling plan in accordance with MIL-PRF-1, table III.
11.
Referenced documents: In addition to MIL-PRF-1, this document references the following: MIL-STD-1311.
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